论文标题
抗抗氟异酸的阴性/正静电效应
Negative/positive electrocaloric effect in antiferroelectric squaric acid
论文作者
论文摘要
使用先前开发的模型，我们研究了缝合酸的抗fififerroelelectric晶体中的电气效应（ECE）。在低温下，预计沿着晶体的电场的极化重新定位预计将是两个阶段的过程，每次Sublattice极化之一切换了两次，每次均为90美元$^\ Circ $。探索了模型两极分化和熵的$ t $ - $ e $景观。以引入的电Grüneisen参数为特征的ECE在抗fiferroelectric阶段被发现为负。在具有垂直倍数极化的中间铁晶相中，在低场处为正，但略低于向铁电相的过渡。在铁电期间，ECE在所有温度和场均为正。预计在200 kV/cm处的最大EC温度偏移幅度将小于-3 k。探索了两个双临界终点之间的跨界区域中格涅森参数的超临界行为。
Using the previously developed model we study the electrocaloric effect (ECE) in antiferroelectric crystals of squaric acid. At low temperatures, the polarization reorientation by the electric field applied along the crystallographic $a$ axis of these crystals is predicted to be a two-stage process, with one of the sublattice polarizations switched twice, by 90$^\circ$ each time. The $T$-$E$ landscapes of the model polarization and entropy are explored. The ECE, characterized by the introduced electric Grüneisen parameter, is found to be negative in the antiferroelectric phase. In the intermediate ferrielectric phase with perpendicular sublattice polarizations it is positive at low fields, but becomes slightly negative below the transition to the ferroelectric phase. In the ferroelectric phase the ECE is positive at all temperatures and fields. Maximal EC temperature shift magnitude is predicted to be just less than -3 K at 200 kV/cm. The supercritical behavior of the Grüneisen parameter in the crossover region between two bicritical end points is explored.
